The present invention relates to substantially flange like rotary components which can be utilized for the reduction of torsional stresses or vibrations in drive trains. The device contains energy storing devices composed of coil springs which serve to transmit torque between a rotary input and an output member forming part of a torsional vibration coupling for use in the powertrain between the prime mover (such as a combustion engine or other torque producing element) and the variable speed transmission and/or another driven unit. More particularly, the invention relates to improvement in the substantially flange like rotary components which are especially suitable for the transmission of torque to or from coil springs which together form an annular energy absorbing device interposed between coaxial input and output members which can rotate about a common axis.
It is well known to employ annular energy absorbing devices of the above outlined character. A first flange is rotatably coupled to and driven by a torque producing element when the mechanism employing such structure is engaged. A second flange is rotatably coupled to the transmission or drive train of the mechanism. The parallel first and second flanges are coupled by energy absorbing devices such as springs disposed between the flanges. The flanges are angularly movable with each other about a common axis and relative to each other about neutral positions.
In situations where the first and second flanges are rotating at the same speed, the spring is in a neutral position. When a torque load is applied to either the input or the output shaft, the relative angular rotation speed or velocity is changed. The plates, while still rotating, will move away from the neutral position compressing the springs and transmitting the load to the other member. The coupling acts to reduce the "shock" between the torque producing and the torque transmitting members.
It is known that due to the stresses seen in the vibration damping apparatus as described above, certain failure modes are observed. These failure modes include wear of the spring components, as well as a substantial amount of wear in the chambers holding these components. This wear reduces the efficiency and durability of the springs and holding chambers and lead to noise, as well as the potential of catastrophic failure of the internal components.
As such, the invention described herein is embodied in an apparatus for dampening vibrations in a powertrain between a torque producing and a torque transmission assembly. The improved apparatus comprises at least two components which are rotatable relative to each other about a common axis and include a first component connectable with the torque producing elements (e.g. with the crankshaft of an internal combustion engine) and a second component which is connectable with the torque transmission assembly (e.g. with the input shaft of a variable speed transmission), and means for transmitting torque between the first and second components. Included within the apparatus is a chamber and/or chambers for holding the spring elements. These chambers are located between the input element and the output element of the apparatus; more particularly, between the input element and the spacer ring of the output element. The apparatus contains with the chambers torsionally elastic dampers or springs. In some instances it may be desirable to include friction materials between the flange members to help dampen vibrations by providing hysteresis or Coulomb friction within the torsional vibration coupling. It has been found that the aforementioned configuration significantly reduces the amount of wear on the spring and flange members of the apparatus.
An optional ledge portion can be provided for separating a portion of the torsional damping member from the spacer ring. This allows contact between the spring and the spacer bar element where there is the minimum translation and/or relative motion of the coupling member, thus reducing wear.
In view of the aforementioned problems, it is an object of the current invention to provide a torsional vibration coupling which reduces the amount of wear on its components.
It is another object of the current invention to provide a torsional vibration coupling which has a reduction in variation of uncontrolled hysterisis.
It is another object of the current invention to provide a torsional vibration coupling where changes in the damping rate during the life of the product is minimized.
It is further an object of the current invention to provide a torsional vibration coupling which is less susceptible to corrosion and which requires less frequent lubrication of its elements.